U.S. Pat. Nos. 4,057,159, 4,059,198 and 4,485,932 disclose child-resistant closure and container prescription packages that include a container or vial, a closure, and a spring/seal disk arrangement disposed between the closure and the container. The closure has lugs on an inside surface of a skirt that cooperate with external locking notches or pockets on projections around the mouth of the container for securing the closure to the container. An internal abutment on the closure cooperates with the spring/seal disk(s) to urge the closure away from the container so that the lugs are resiliently captured within the notches. When it is desired to remove the closure, the closure is pushed toward the container so that the lugs clear the notches, and then turned counterclockwise. When the closure is assembled to the container, the lugs cam beneath surfaces on the projections against the force of the spring seal disk(s) until the lugs snap into the notches on the projections.
Although the closure and container packages disclosed in the noted patents have enjoyed substantial commercial acceptance and success, improvements remain desirable. For example, it is desirable to minimize the complexity of the design and manufacture of closure and container packages by reducing the quantity of parts thereof. Accordingly, it is a general object of the present invention is to provide a two-piece package of the subject type—i.e., a closure and a container without a separate spring element or self-resilient spring-like members—in which the spring forces for holding the closure on the container are provided by resilient flexure of the closure. It is a related object to provide a simple closure and container package that does not require delicate spring-like members. Accordingly, it is possible to produce more robust mold tools that do not have correspondingly delicate mold features, wherein the mold tools have a longer service life.
The present invention embodies a number of aspects that can be implemented separately from or, more preferably, in combination with each other.
A package in accordance with one aspect of the invention includes a container having an open end surrounded by a cylindrical wall, a plurality of external projections on the wall, notches on undersides of the projections, and external cam surfaces on the projections that incline radially inwardly and axially toward the open end. A closure has a base wall with a skirt, a plurality of internal locking lugs on the skirt, and a plurality of internal cam lugs on the skirt that are disposed between the locking lugs and the base wall. As the closure is applied over the end of the container and the locking lugs are received in the notches, the internal cam lugs engage the external cam surfaces on the projections to spread the skirt and bias the locking lugs into the notches. A two-piece package in accordance with the present invention thus eliminates any need for additional spring/seal disk elements in the assembly.